1. Field of the Invention
This invention relates to a gas turbine apparatus, and more particularly to a exhaust gas recirculating type combined cycle plant wherein exhaust gas is recirculated to an air intake side of a compressor.
2. Description of Related Art
Japanese Unexamined Patent Application No. Hei7-34900 disclosed an exhaust gas recirculating type combined plant wherein a part of exhaust gas from a gas turbine is returned to an air intake of a compressor so as to raise a compressor air intake temperature so that a combustion temperature at the time of partial loading or gas turbine exhaust gas temperature is prevented from dropping thereby preventing a drop in cycle heat efficiency at the time of the partial loading.
Further, according to Japanese Unexamined Patent Application No. Sho 56-141040, before recirculated combustion gas enters a compressor, water is sprayed so that it is vaporized. A cooling unit is provided on a compression air path out of the compressor and by supplying coolant medium, heat is recovered so that a rate of heat recovery from exhaust gas is improved.
However, the Japanese Unexamined Patent Application No. Hei7-34900 does not disclosed anything about widening a range in which high efficiency partial load operation is enabled by stabilized recirculation of exhaust gas. Further, Japanese Unexamined Patent Application No. Sho56-141040 does not mention anything about a partial load operation.
The combined cycle plant has such a feature that there exists an atmospheric temperature maximizing its plant efficiency and the plant efficiency drops at other temperatures than the atmospheric temperature.